Biomedical subjects

Charles D Fraser

Publications and source records attributed to Charles D Fraser.

57 records · Page 4Linked to original sources

PubMed2002

Pulmonary-to-systemic blood flow ratio effects of sevoflurane, isoflurane, halothane, and fentanyl/midazolam with 100% oxygen in children with congenital heart disease.

UNLABELLED: The cardiovascular effects of volatile anesthetics in children with congenital heart disease have been studied, but there are limited data on the effects of anesthetics on pulmonary-to-systemic blood flow ratio (Qp:Qs) in patients with intracardiac shunting. In this study, we compared the effects of halothane, isoflurane, sevoflurane, and fentanyl/midazolam on Qp:Qs and myocardial contractility in patients with atrial (ASD) or ventricular (VSD) septal defects. Forty patients younger than 14 yr old scheduled to undergo repair of ASD or VSD were randomized to receive halothane, sevoflurane, isoflurane, or fentanyl/midazolam. Cardiovascular and echocardiographic data were recorded at baseline, randomly ordered 1 and 1.5 mean alveolar anesthetic concentration (MAC) levels, or predicted equivalent fentanyl/midazolam plasma levels. Ejection fraction (using the modified Simpson's rule) was calculated. Systemic (Qs) and pulmonary (Qp) blood flow was echocardiographically assessed by the velocity-time integral method. Qp:Qs was not significantly affected by any of the four regimens at either anesthetic level. Left ventricular systolic function was mildly depressed by isoflurane and sevoflurane at 1.5 MAC and depressed by halothane at 1 and 1.5 MAC. Sevoflurane, halothane, isoflurane, or fentanyl/midazolam in 1 or 1.5 MAC concentrations or their equivalent do not change Qp:Qs in patients with isolated ASD or VSD. IMPLICATIONS: Sevoflurane, halothane, isoflurane, and fentanyl/midazolam do not change pulmonary-to-systemic blood flow ratio in children with atrial and ventricular septal defects when administered at standard anesthetic doses with 100% oxygen.

Adolescent↗

PubMed2002

Internet use in families with children requiring cardiac surgery for congenital heart disease.

OBJECTIVE: We sought to document the prevalence of Internet access and usage patterns among families who have children with congenital heart disease presenting for cardiac surgery. DESIGN: A cross-sectional study was performed utilizing a questionnaire (10 questions) as the study tool. Statistical analysis was performed on all completed questionnaires. The chi(2) test was used to evaluate categorical variables and the t test to evaluate continuous variables. RESULTS: Two hundred seventy-five questionnaires were completed and analyzed. Thirty-seven percent (102/275) of the children had a cyanotic congenital heart defect. There were 21 children with Trisomy 21. Fifty-eight percent (160/275) of families had access to the Internet. The most common locations for accessing the Internet were home (80%; 129/160) and work (51%; 82/160). There were no significant differences in Internet access with regards to underlying individual congenital heart defect, cyanotic versus acyanotic heart defects, or congenital heart defects with functional univentricular hearts versus biventricular hearts. Families with older children (12--24 years) were more likely to have Internet access. Families of children undergoing placement of a right ventricle to pulmonary artery conduit were more likely to have Internet access. Of the 160 families with Internet access, 58% (93/160) used the Internet to obtain information related to their child's cardiac diagnosis. Eighty-two percent (76/93) characterized locating cardiology-related information as easy. Six parents created interactive personal Web sites specifically related to their child's congenital heart defect. Although families with older patients (12--24 years) were more likely to have access to the Internet, this did not translate into greater use of the Internet to obtain cardiology-related information. Among families who accessed the Internet for cardiology-related information, 95% (88/93) of families characterized the information as helpful or very helpful in furthering the understanding of their child's heart defect. CONCLUSION: Families are utilizing the Internet to educate themselves about congenital heart disease. Most parents consider the process easy and the information obtained helpful to the understanding of their child's congenital heart defect and surgery. Internet use in this patient population is expected to increase. Our vigilance in providing accurate Internet references, as well as in identifying inaccurate Internet information available to our patients and their parents, is of paramount importance.

Adolescent↗

PubMedDate not supplied

Pulsatile perfusion improves regional myocardial blood flow during and after hypothermic cardiopulmonary bypass in a neonatal piglet model.

Pediatric myocardial related morbidity and mortality after cardiopulmonary bypass (CPB) are well documented, but the effects of pulsatile perfusion (PP) versus nonpulsatile perfusion (NPP) on myocardial blood flow during and after hypothermic CPB are unclear. After investigating the effects of PP versus NPP on myocardial flow during and after hypothermic CPB, we quantified PP and NPP pressure and flow waveforms in terms of the energy equivalent pressure (EEP) for direct comparison. Ten piglets underwent PP (n = 5) or NPP (n = 5). After initiation of CPB, all animals underwent 15 minutes of core cooling (25 degrees C), 60 minutes of hypothermic CPB with aortic cross-clamping, 10 minutes of cold reperfusion, and 30 minutes of rewarming. During CPB, the mean arterial pressure (MAP) and pump flow rates were 40 mm Hg and 150 ml/kg per min, respectively. Regional flows were measured with radiolabeled microspheres. During normothermic CPB, left ventricular flow was higher in the PP than the NPP group (202+/-25 vs. 122+/-20 ml/l 00 g per min). During hypothermic CPB, no significant intragroup differences were observed. After 60 minutes of ischemia and after rewarming (276+/-48 vs. 140+/-12 ml/100 g per min; p < 0.05) and after CPB (271+/-10 vs. 130+/-14 ml/100 g per min; p < 0.05), left ventricular flow was higher in the PP group. Right ventricular flow resembled left ventricular flow. The pressure increase (from MAP to EEP) was 10+/-2% with PP and 1% with NPP (p < 0.0001). The increase in extracorporeal circuit pressure (ECCP) (from ECCP to EEP) was 33+/-10% with PP and 3% with NPP (p < 0.0001). Pulsatile flow generates significantly higher energy, enhancing myocardial flow during and after hypothermic CPB and after 60 minutes of ischemia in this model.

Animals↗